Water Rocket Forum

Welcome to the Water Rocket Forum, sponsored by The Water Rocket Achievement World Record Association.

The largest, most sophisticated and ground breaking group supporting you, the serious water rocket flyer! Whether you are a beginner or an expert, the WRA2 has something for everyone.

A water rocket is a type of model rocket using water as its reaction mass. The pressure vessel (the engine of the rocket) is constructed from thin plastic or other non metallic materials (usually a used plastic soft drink bottle) weighing 1,500 grams or less. The water is forced out by compressed air. It is an example of Newton's third law of motion.

Well I think I'm going to have another stab at the class B record next year, and wanted to get something sorted out.

After seeing USWR's servochron timer II release I thought it might be time to upgrade to electronic deployment. They've certainly made it easy. But then I saw Air Command's servo timer II, and that one just fits my needs better. So if I used their timer would I still be eligible to compete? I really like making my own stuff, but things like this just make more sense to produce in a bit of volume, and I think that's the main reason George even sells the flight computers. So what does everyone think?

SaskAlex wrote:Well I think I'm going to have another stab at the class B record next year, and wanted to get something sorted out.

After seeing USWR's servochron timer II release I thought it might be time to upgrade to electronic deployment. They've certainly made it easy. But then I saw Air Command's servo timer II, and that one just fits my needs better. So if I used their timer would I still be eligible to compete? I really like making my own stuff, but things like this just make more sense to produce in a bit of volume, and I think that's the main reason George even sells the flight computers. So what does everyone think?

Alex

Hi Alex,
Technically the timer would be considered a "commercial product" and thus would not be allowed for use in the competitions.

Secion I-7 of the competition rules states: Rocket must be completely scratch-built using materials which are not manufactured for model rocket parts. (with the exception of the Camera and Altimeter) Raiding hobby shops for nosecones, or fins, or any other pre-manufactured items is prohibited.

However, in the interest of furthering good relations amongst the water rocket community, we could have a vote amongst the membership to allow an exemption for the "servo timer II" and allow it's use in the competitions.

A vote will be carried out to allow an exemption for use of the "servo timer II" in world record competition. The poll will be setup in the association business forum: http://www.wra2.org/forum/viewforum.php?f=32 and will last until Nov 6th, 2011.

SaskAlex wrote:Well I think I'm going to have another stab at the class B record next year, and wanted to get something sorted out.

After seeing USWR's servochron timer II release I thought it might be time to upgrade to electronic deployment. They've certainly made it easy. But then I saw Air Command's servo timer II, and that one just fits my needs better. So if I used their timer would I still be eligible to compete? I really like making my own stuff, but things like this just make more sense to produce in a bit of volume, and I think that's the main reason George even sells the flight computers. So what does everyone think?

Alex

Hi Alex,

I'm not sure if anyone else has already suggested it on the link above, (I don't have permission to view the thread), but if you like to make your own, and size and weight are really critical for your record attempt, you might want to check this one out:http://www.hvwtech.com/products_view.asp?ProductID=1056 It's tiny, inexpensive and I think it would be suitable for parachute deployment. Programming is also very easy with the serial cable, and there are lots of software libraries already for these ICs. You should be able to easily adapt one of the servo driving routines for timed deployment. You could also solder one of the tiny Assemtech G-switches to the board for launch detect. You wouldn't really need any other external switches as you could set servo motor positions, or the delays through the serial interface. Hopefully you also shouldn't have any "commercial rocket product" issues with the rules.